Multi-conductor electrical connector



Sept. 19, 1961 R CHESNUTT ETAI- 3,001,167

MULTI-CONDUCTOR ELECTRICAL CONNECTOR Filed Feb. 7, 1958 5 Sheets-Sheet 1 20 25 20 25/ 4 fig 1 36 7 P401. J. P4 SH/VEI? ATTORNEY P 19, 1961 J. R. CHESNUTT ETAL 3,001,167

MULTI-CONDUCTOR ELECTRICAL CONNECTOR Filed Feb. '7, 1958 i2 40 so 3 Sheets-Sheet 2 EL T 1 -5- 56 z #1 INVENTORS l/flMES R. Cues/v07? P404 M PLISH/VE/F ATTORNEY S 19 1 J. R. cHEs'Nu-rT ETAL MULTI-CONDUCTOR ELECTRICAL CONNECTOR Filed Feb. '7, 1958 3 Sheets-Sheet I5 INVENTORS J/w/Es P. CHE-SNUTT PHUL zlPz/smvs) B Y lam/2 ATTORNEY United States Patent 3,001,167 MULTI-CONDUCTOR ELECTRICAL CONNECTOR James R. Chesnutt, P.0. Box 107, Star Route, Orange,

Cal1f., and Paul J. Plishner, Cavalry Road, Westport, Conn.; said Chesnutt assignor to said Plishner Filed Feb. 7, 1958, Ser. No. 713,820

r 13 Claims. (Cl. 339-459) I 01' recesses.

The other connector member carries a plurality of (correspondingly arranged) upstanding metal pins or rods slidably registering with the respective recesses to effect electrical interconnections between the rods and well contacts upon intercoupling of the connector members. These separable electrical connectors possess numerous drawbacks and disadvantages and leave much to be desired. Great care must be exercised in accurately aligning the contact pins with the respective wells in coupling the connector members which may often be undesirably timeconsuming. The contact pins are easily damaged and subject to short-circuiting. Furthermore, the conventional multi-element electrical connector cannot be substantially miniaturized, particularly by reason of the minimum spacing required between the contact pins to mininiize short-circuiting or flashover, and the minimum diameter of the contact pins for necessary structural strength.

It is therefore a principal object of the present invention to provide an improved electrical connector device,

which by nature of a basic change in configuration, eliminates or minimizes the aforementioned disadvantages of conventional electrical connector devices.

Another object of the present invention is to provide an improved multiple-contact type separable electrical connector. l i

Still another object of the present invention is to provide an improved multiple-contact separable electrical V connector of simple and rugged construction.

' A further object of the present invention is to provide an improved multiple-contact separable electrical connector characterized by the ease in effecting the coupling and uncoupling thereof.

Still a further object of the present invention is to provide an improved multiple-contact separable electrical connector in which engagement between the respective contact elements is simultaneously effected. 1

Another object of the present invention is to provide an improved multiple-contact separable electrical connector which is subject to great miniaturization.

The above and other objects of the present invention will become apparent from a reading of the following description, taken in conjunction with the accompanying drawings which illustrate preferred embodiments of the present invention as well as a preferred improved method for fabricating the same, wherein FIGURE 1 is an enlarged perspective view ofa metal tubular member which is employed in producing the plug contact elements;

FIGURE 2 is an enlarged perspective view, illustrating the arrangement of the semi-finished contact elements and the attached conductors in position for assembly into the plug member;

FIGURE 3 is an enlarged side elevational viewof the plug member in semi-finished condition;

a knurled peripheral surface.

Patented Sept. 19, 1961 FIGURE 4 is a sectional view taken along line 4-4 in FIGURE 3;

FIGURE 5 is an enlarged side elevational view of the improved plug member, illustrated partially broken away and partially in section;

FIGURE 6 is a sectional view taken along line 6--6 in FIGURE 5;

FIGURE 7 is an enlarged perspective view of a pair of segments employed in fabricating the inner shell of the improved socket member;

FIGURE 8 is an enlarged side view of the finished improved socket member, illustrated partially broken away and partially in section;

FIGURE 9 is a sectional view taken along line 9-9 in FIGURE 8;

FIGURE 10 is an enlarged sectional view taken along line 10-40 in FIGURE 8, the plug member being illustrated in registering but non-coupled position;

FIGURE 11 is a view similar to FIGURE '10, partially broken away for convenience of illustration, showing the plug and socket member in completely coupled position;

FIGURE 12 is an enlarged side view of another modification of the plug and socket member of the present invention, illustrated partially broken away;

FIGURE 13 is an enlarged detailed bottom view of the embodiment illustrated in FIGURE 12, shown partially in section and partially broken away;

FIGURE 14 is a side elevational View of another embodiment of the present invention, illustrated partially broken away, wherein the socket member is shown mounted on the face of a chassis;

FIGURE 15 is a side elevational view of a further embodiment of the present invention;

FIGURE 16 is a side elevational view of still a further embodiment of the present invention;

FIGURE 17 is an enlarged side elevational view of the shank of the plug member of another embodiment of the present invention;

FIGURE 18 is an enlarged transverse cross sectional 'view of the socket member of another embodiment of the present invention; and

FIGURE 19 is an enlarged side elevational View, partially broken away and partially in section of still another embodiment of the present invention.

In a sense, the present invention contemplates the provision of an electrical connector comprising a socket member; a plurality of longitudinally spaced mutually insulated contact elements disposed within said socket member; a slidably mating plug member; a plurality of longitudinally spaced mutually insulated second contact elements disposed along said plug member; and means maintaining a predetermined angular orientation between said plug and socket members during sliding coupling thereof and permitting relative rotation thereof at the terminus her and the numeral 11 a mating socket or female connector member. The plug 10 is formed of an insulating material such as thermoplastic or thermosetting resin and includes a longitudinally extending shank 13 having a tapered frusto-conical leading end 14 and provided at its trailing end with an enlarged cylindrical head 16 which defines a finger manipulating piece and is provided with The shank 13 is of substantially circular transverse cross section andis pro- 3 vided with diametrically opposite longitudinally extending flat surfaces 17 extending from the tip thereof to a point short of the head 16, the flats 17 being closer to the axis of the shank 13 than the remaining arcuate peripheral surface thereof.

iLocated on one of the arcuate surfaces of the shank 13 area pair of longitudinally spaced upright projections 18 having substantially parallel side walls, the forward .projecticn'being immediately posterior to the leading end of the shank 13 and the rear projection being just forward of the plug'head 16. On the opposite arcuate surface of the shank 13 are located longitudinally spaced prismatic projections 19 which are diametrically opposite .to the respective projections 18.

vA set of longitudinally spaced'andlongitudinally aligned arcuate shaped metal contact elements 20 are embedded in the'shank-13 along oneof the arcuate peripheral surfaces thereof. The contact elements 20 extend circumferentially forless than 180 and their outer surface is coplanar withthe arcuate peripheral surface ofthe shank 13 and their edges coplanarwith the flats 17-. Another set'of longitudinally spaced longitudinally aligned'arcurate contact elements 21 are disposed opposite to the re spective contact elements 20 and are laterally aligned therewith, the outer surface of the elements 21 being coplanar with the arcuate surface of the shank 13, the end edges of corresponding pairs ofcontact elements 20 and Y421 -being laterally spaced from each other. Formed in the outer surface of each of the contact elements 20, 21

intermediate the ends thereof is an arcuate recess 22.

Connected to each of the contact elements 21 and 21 is an insulator covered conductor 23 the end of which .13 soldered to a corresponding contact element, the condoctors 23 being embedded in the shank 13 and extending longitudinally through the trailing end thereof. A pair of radially projecting pins 24 and 26 respectively are carried on the surface of the 'plug head 16 and are circumferentially spaced approximately 90, the'pins functioning with associated latching means, as will be hereinafter set forth.

In FIGURES 1 through 4 of the drawings there are illustrated successive steps of a preferred method of forming theimproved plug shown in FIGURES and 6 of the drawings. The contact elements are fabricated from .a-tubular member 27 formed of brass or other suitable conducting material, the tubular member 27 having oppositely disposed longitudinally extending grooves 28 formed ductors 23 are then located in a suitable mold in longiitudinally spaced coaxial arrangement and a suitable thermoplastic or thermosettingresin introduced into the mold-sothat the unfinished plug is formed having the rings 30 embedded in the surface of the shank portion -with the grooves 28 and 29 thereof being in longitudinal alignment, the conductors 23 extending longitudinally rearwardly through the shank 13 and projecting through the trailing end of the plug 10.

The method of casting and the method of locating the :rings 3% may be eifected in any conventional manner. "Thereafter, a pair of oppositely disposed longitudinal secntors are removed from the shank 13 as by grinding or the like, in the proximity of the longitudinal grooves 29 corresponding portions of the rings 30 being removed until eachof the rings 30 is divided into .a pair of separate segments or contact elementsZil-and '21, and the flats 1-7 are formed.

.spacing between successive recesses the same as the spacing between successive plugcontact extends from one end The female or socket member 11 includes a longitudinally extending inner shell 32, preferably formed of an insulating plastic material in. any well known manner and terminating at its trailing end in an enlarged head 33 of hexangonal cross section. A-pair of oppositely disposed longitudinally extending grooves 134 and 36 respectively are formed in the inner face of theshell 32 a'nd extend from the open trailing end thereof to a point short of the leading end. The groove 34 is of channel-shaped transverse cross section correspondingin shape to the plug protuberance 18, and the groove 36 is of triangular transverse cross section corresponding in shape to the ,plug protuberance .19 to permit sliding engagementbetween the corresponding grooves .and plug protuberances and permitting sliding engagement between the plug and socket only at a predetermined orientation or polarization when the protuberances 18 and :19 register with the grooves 34 and 36. I

The grooves 34 and 36 (at their leading end) terminate in and communicate with circumferentially extending channel shaped grooves 37 which extend approximately counterclockwise as viewed forwardly from the head :portion 33. Also formed in'the inner faceof the shell 32 in the neighborhood of the head portion33 .area pair of oppositely disposed channel-shaped circumferential grooves 38 which extend counterclockwise from. each of the longitudinal grooves 34 and 36 for approximately 90. The longitudinal spacing between the .grooves 37 and 38 is equal to the longitudinal spacing between the plug protuberances 18 and 19. Thus, the plug 10 may be inserted into the socket 11 upon proper polarization,

.and following the full insertion of the plug withinthe socket the plug may be rotated clockwise 90, as viewed .from the open end of the socket, the protuberances 18 .and 19 engagingthe grooves 37 and 38.

Formed in theinner face of the inner-shell 32 are two diametrically opposed longitudinal sets of circumferentially extending channel-shaped recesses ;40'which are disposed between the grooves 34 and 36. The center 40 is substantially elements 20 or 21, andthe recesses 40 of the opposite ;sets are laterally aligned. Disposed in each of the recesses 40is a contactelement 41 formedof a resilient strip of metal. Each of the contact elements41includes a curved section 42 having its convex portion directed inwardly towards the axis of the shell 32 and provided with a centrally facing protuberance 43 adapted to engage recess 22 formed in the corresponding plug.

contact element .20 or 21. Radially projecting arm144 of the contact element curved portion 42 through the wall of the inner shell 32 and terminates in a circumferentially extending leg 46 which is. substantially superimposed upon the outer wall'of the inner shell 32, The free end of the contact element curved portion 42 is oppositely bent, as at 47,-and bears againstthe base of the corresponding recess 40. The crown of the contact element convex portion 42 as well as the protuberance 43 projects inwardly of-the inner cylindrical wall of the shell 32 when in normal unstressed condition. The contact elements 20, 21 and 41 may be formed of any suitable conducting material such as brass or the like and are preferably electroplated in accordance with conventional practice with palladium or other suitable metal to provide greater corrosion and abrasion resistance and a better electrical contact surface.

-An intermediate cylindrical shell 49 is formed of an insulating material such as a plastic material and may be integrally formed with the inner shell 32 or firmly adhered thereto. The legs 46 of the contact elements 41 are embedded in the inermediate shell 49 and are connected to insulator coveredconductors 50 whichare also embedded in the intermediate shell 49 and extend longitudinally in thezwall of the shell through the'ileading end thereof. It should be noted that the insulation covering 50 as well as those covering the conductors 23 associated with the connector plug member may be color coded in the well known manner. A tubular metal shell 51 tightly engages the intermediate shell 49, the leading edge thereof being inwardly inclined as at 55, to engage the corresponding beveled surface of said intermediate shell.

A latching member 52 is carried by the socket member 11 and includes an annulus 53 trapped between the underface of the head portion 33 and the confronting faces of the intermediate and outer shells 49 and 51. A longitudinally extending resilient leg 54 extends rearwardly from the outer edge of the annulus 53 and abuts a peripheral face of the head 33. The leg 54 terminates in an outwardly directed cam section 56, immediately forward of which is disposed a circular aperture 57 formed along the medial longitudinal axis of the arm 54. The portion of the arm extending laterally from the opening 57 is outwardly inclined, as at 58. The latching member 52, as will be hereinafter set forth, cooperates with the pins 24 and 26 disposed on the head 16 of the plug member to permit the locking of the plug in the socket in coupled, contact open or contact closed position.

In accordance with the preferred method of fabricating the socket member 11 the inner shell 32 is formed of a pair of substantially similarly shaped complementary segments 60, each of the segments defining one-half of the inner shell 32 split along a diametrically extending plane intersecting the recesses 40. A contact element 41 is located in each of the recesses 40 of one of the segments 60, the arm 44 thereof extending radially outwardly through a groove 61 formed in the shell wall between successive recesses. The shells 60 are then assembled and maintained in any suitable fashionin assembled condition with each of the recesses carrying a corresponding contact 41. A conductor 50 is then connected to each of the contact legs 46 and is drawn along the outer face of the shell 32 beyond the leading end thereof. The latching member 5'2 is then slid over the shell 32 into contact with the underface of the head 33 and the metal shell 51 drawn over the bunched conductors 50 and into coaxial registry with the inner shell 30. Thereafter, a suitable pitch or potting resin is poured in the space between the confronting faces of the shell 32 and the outer metal shell 51 and is permitted to set to finish the assembly of the female or socket connector member.

In coupling the plug and socket member the plug 10 is aligned with and oriented relative to the socket member 11 so that the protuberances 18 and 19 engage the longitudinal grooves 34 and 36 respectively. The plug is then slid into full registry with the socket member 11, the pin 26 riding under the cam section 56 of the arm 54 to raise the same and bringing the pin into registry with the arm aperture 57. As the plug 10 is slid into the socket 11 the flats 17 thereof confront the socket contact elements 41, whereas the plug contact elements 20 and 21 do not engage the contact elements 41 but merely slide along the inner surface of the insulating shell In order to effect engagement between the contact plug elements 20 and 21 and the socket contact elements 41 the arm 54 is raised to effect disengagement between the aperture 67 and the pin 26, and the plug is rotated counterclockwise, as seen in FIGURE 10 of the drawing, until the pin 26 engages aperture 51. In this latter position the plug and socket are in coupled contact closed position. As the plug 10 is rotated relative to the socket 11 the plug contact elements are conveyed along the socket contact elements 11 resiliently urging the latter forwardly until the contact recesses 22 are in registry with the contact protuberances 43 in which position the pin 26 is in registry with the aperture 57, and the plug and socket are in contact closed position.

The reverse procedure is followed in efiecting a contact open position and subsequently uncoupling the plug from the socket.

In FIGURES 12 and 13 of the drawings, there is illusrtrated another embodiment of the present invention differing from the preferred embodiment above described in that the socket member has the polarizing channels formed in its outer surface and the plug member is provided with a hollow coaxial tubular shell spaced from the plug shank and having inwardly directed protuberances adapted to engage the socket channels. More particularly, the plug member 10 includes a hexagonal head 33 and a longitudinal shank 13 carrying contact elements 20 and 21, the construction of the plug member being similar to that previously described except that it lacks the shank protuberances 18 and 19.

The plug member 10 is provided with a tubular open ended shell 70 arranged coaxially with the plug shank 13 and extending from the head 33 to a point just forward of the leading end of the shank 33. The trailing end of the shell 70 is provided with an inwardly directed flange '71 which is embedded and affixed to the head 33 which serves as a support and mount for the shell 70, the peripheral surface of the shell 70 being substantially at the level of the mid points of the sides of the hexagonal head 33. For-med on the inner surface or the shell 70 are a pair of lower longitudinally spaced inwardly directed protuberances 72 of rectangular transverse cross-section and a pair of longitudinally spaced upwardly directed protuberances 73 of triangular transverse cross-section, the respective protwberances 72 and 73 being diametrically opposed. The head :33 of the plug member carries a latching member 74 which includes a resilient forwardly extending arm 76 having a channelshaped trailing end anchored to the head 33 and tenninating at its free end in an outwardly inclined leg 77. Immediately rearwardly of the leg 77 is disposed an inwardly directed latching pin which is in slidable registry with an aperture formed in the shell 70.

The female or socket member 11 is similar in construction to the socket member of the first embodiment except that the inner shell 32 lacks the grooves 34, 36, 37 and 38. In place thereof, there is formed in the outer metal shell 51 an upper longitudinally extending groove 78 of triangular transverse cross-section extending from the trailing edge of the shell 51 to a point short of the leading end thereof and a diametrically opposed longitudinally extending groove 79 of rectangular transverse cross-section also extending from the trailing edge of the shell 51 to a point short of the leading end thereof.

Extending circumferentially counterclockwise from each of the grooves 78 and 79 for approximately 90 are a pair of rear channel-shaped grooves 86 and a pair of forward channel-shaped grooves 81, the distance between the grooves 80. and 81 being equal to the longitudinal distance between protuberances 72 and protuberances 73. In all other respects, the plug and sockets are similar to that previously described.

In effecting a coupling between the plug 10 and the socket 11, the shell 70 is orientated with respect to the shell 51 so that the plug protuberances 72 and 73 are in longitudinal alignment with the respective grooves 78 and 79. The plug is then slid into full registry with the socket until the plug protuberances 72 and 73 are aligned with the circumferential grooves 80 and 81, whereupon the plug is rotated counterclockwise. During the sliding engagement between the plug and socket there is no engagement between the respective contact elements, engagement being effected only upon rotation of the plug relative to the socket following the complete registry between the plug and socket. It should be noted that the latching pin 75 is so located as to be disposed on the outer surface of the shell 51 upon the coupled contact open position of the connectors. However, upon rotatihn of the plug to a contact closed position, the pin 75 registers wwiththe groove 80 at a terminus of the groove to thereby prevent relative rotation of the plug and socket unless the pin is raised at least to the level of theouter surface ofthe shell 51.

-In'FIGURE 14 of the drawing, there is illustrated a plug and socket arrangement in which the socket is nibuntedon a Wall 86 f a chassis. The plug member 10 is similar in construction to that of the embodiment "firstdescribed, and the socket member 11 is similar in construction to the socket member first described. In

mounting-the socket member 11 on the wall 86 0: a chassis, the shell 51 registers with a circular opening formed in the chassis wall 86', the hexagonal head 33 abutting'the outer face of the wall 86. A suitable lock ring 87 of conventional construction engages the shell 51 and tightly abuts the inner face of the wall 36 to suitably support the socket member. It should be noted that inasmuch as the plug member is disposed within a chassis housing, the metal outer shell 51 may be obviated, in which case the outer surface of the plug 11 is defined by the intermediate shell 49.

.Referring now to FIGURE 15 of the drawing, which illustrates another embodiment of the present invention, thesocket members 11 are similar in construction to the socket members first described. The plug member 11%, however, is provided with oppositely directed shanks 90 which extend from an intermediate cylindrical coaxial head portion 91. Each of the shanks 90 are provided with contact elements and 21 and the protuberanees '18 and 19 as previously described. The conductors connected to each of the contact elements 20 and 21 may 'be interconnected in any desired arrangement or may extend outwardly from the head portion 91. The plugs and sockets are coupled in the manner previously described. ;It should be noted that the contact elements of the pair of socket members ll may be interconnected in various preselected arrangements by providing a plurality of plug members 110, and the contact elements 20 and 21 of which are correspondingly interconnected.

In FIGURE 16 of the drawing, there is illustrated another embodiment of the present invention which is the counterpart of that illustrated in FIGURE 15 in that there are provided apair of plug members 10 and a socket member 11 1 having entrance openings at both ends thereof. The plug members 10 are similar in construction to those first described, whereas the socket member .111 is double ended, constituting a pair of complementary socket elements similar to the socket member 11 but integrally coaxially joined at their leading ends. Here again, the contact elements of the socket 111 may be interconnected or the conductors connected to the contact elements may extend outwardly from the socket member. As in the previous embodiment, the connection between the contact elements of the plug members 10 maybe connected in any predetermined arrangement by employing a plurality of socket members 11 in which the contact elements thereof are correspondingly connected.

.In FIGURE 17 of the drawing, there is illustrated a shank 1'3 of a plug member in which the contact elements 20 and .21 of the longitudinal sets are arranged in staggered relationship. In the mating socket member, the contact elements are likewise arranged in staggered relationship. The advantage of staggering the contact elements .20 and ,21 is to provide a greater spacing between-opposite contact elements and thereby increase the allowable potential differences between them.

In FIGURE 18 of the drawing, there is illustrated another form of socket member which comprises a body portion-1.01 stnuctu'rally similar to the inner shell 32 of thesocket member 11 first described. The body mem- 1ber;101 is provided with longitudinally extending grooves 34-: and 36 as well as connecting circumferentially extendinggrooves. .In each of the recesses 40 formed in the inner surface of the body member 101 is housed a resilient contact element .102, which includes. a curved section 103 member 10 1 and is firmly afiixed thereto. The various connections to the respective contact elements 103 are made by way of the corresponding lugs 104.

In the embodiment of the present invention illustrated in FIGURE 19 of the drawing, the coupled plug and .soc'ketmembers are substantially enclosed in a capped metal casing. The plug member includes a shank 13 prosided with the contact elements 2d and 21 as previously described, and has formed at its trailing end a pair of longitudinally spaced front and rear peripheral flanges 113and 114 respectively. An internallytthreaded-cap member 116 has a forwardly directed opening andan end Wall having a circular aperture 117 registering with that portion of the shank 13 disposed between the flanges 113 and 114, the inner face of the end Wall confronting and engaging the trailing face of the flange 113.

The socket member is designated generally bythenulmeral 118 and is enclosed in a tubular casing 11% having a thread formed on its trailing outer surface. The interior construction of the socket 1l8is similar to that of the previously described socket member 11. In coupling the plug and socket members, they are brought into registry as previously described, the cap member 116 being urged to itsrearmost position against the flange 114. If it is desired that the coupling be effected in contact open position, the cap member 116 is brought into engagement the thread 12%) and suitably tightened. However, if it is desired to lock the plug and socket in contact close position, the plug is rotated relative to the socket to effect engagement between the respective contact elements prior to tightening the cap 116 onto the'housing 11 9.

This arrangement permits the carrying of heavier currents by the larger contact elements. The mating socket member is correspondingly shaped in a complementary manner.

We claim:

1. An electrical connector comprising a socket member, a plurality of longitudinally spaced mutually insulated first contact elements disposed within said socket member,

a slidably matingplug member, a plurality of longitudinally spaced ,mutually insulated second contact elemer ts-disposed along said plug member, and separate means other than the contact elements to maintain a singlepredetermined angular orientation between said plug and socket members during sliding coupling thereof and limiting relative rotation thereof at the terminus ,of said sliding coupling to a single predetermined directional sense, said means including a plurality of grooves differ- .ently shaped in transverse section extending longitudinally of one of the plug and socket members, and a plurality of protuberances correspondingly difierently shaped in transverse section extending from the other of the plug and socket members, said first and second contact elements being out of engagement at said predetermined orientation and in engagement upon rotation from said predetermined relative orientation to a closed contact position.

2. An electrical connector in accordance with claim 1, wherein said second contact elements are provided with peripheral-surfaces concentric with the axis ofrotation ofsaid-plug of less than 360, and the elements and the insulation separating them from each other form a smooth 9 continuous arcuate surface extending lengthwise of the plug.

3. An electrical connector in accordance with claim 1, including a plurality of longitudinally aligned sets of said longitudinally spaced second contact elements and a corresponding plurality of longitudinally aligned sets of said first longitudinally spaced contact elements where in the peripheries of said sets of second contact elements are of arcuate configuration extending circumferentially of the plug member for less than 360 and in a straight line, lengthwise of the connector.

4. An electrical connector in accordance with claim 3, wherein said second contact elements of said plurality of aligned sets are longitudinally staggered relative to each other and said first contact element and said plurality of aligned sets are longitudinally staggered relative to each other.

5. An electrical connector in accordance with claim 3, wherein said contact elements are in transverse alignment.

6. An electrical connector in accordance with claim 2, wherein said second contact elements are of arcuate con figuration extending circumferentially for less than 180.

7, An electrical connector in accordance with claim 1, wherein the peripheries of said second contact elements are of arcuate configuration extending circumferentially of the plug member for less than 360 and in a straight line lengthwise of the plug.

8. An electrical connector in accordance with claim 1, wherein said socket member includes a well portion defined by a cylindrical wall, the inner surface thereof having longitudinally spaced recesses formed therein, said first contact elements being located in said recesses and normally projecting above the upper edges thereof and being resiliently inwardly urged by said second contact elements during engagement therewith, and including lugs connected to said first contact elements and projecting through said cylindrical wall.

9. An electrical connector in accordance with claim 1, wherein said plug member comprises a longitudinally ex- 10 tending shank carrying said second contact elements and including a spaced open ended cylindrical shell surrounding said shank, said socket member including a longitudinally extending rod slidabiy registering with said shell and a well carrying said first contact elements slidably engaging said shank.

10. An electrical connector in accordance with claim 9, wherein said rod and said shell have confronting faces, one of said faces having formed therein a longitudinally extending groove terminating in a circumferentially extending groove and the other face being provided with a protuberance slidably engaging said groove.

11. An electrical connector in accordance with claim 1, wherein one of said connector members is provided with an externally threaded cylindrical surface and the other of said connector members is provided with a rotatable internally threaded cap adapted to engage said externally threaded surface when said connector members are in coupled position.

12. An electrical connector in accordance with claim 1, wherein said plug member is provided with a pair of oppositely directed longitudinally extending shanks, each carrying a plurality of said longitudinally spaced second connector elements and including a pair of said socket members adapted to engage said shanks.

13. An electrical connector in accordance with claim 1, wherein said longitudinally extending groove terminates in a circumferentially extending groove disposed forward of the frontmost of said contact elements.

References Cited in the file of this patent UNITED STATES PATENTS 1,265,163 Bahls etal. May 7, 1918 2,434,534 Alford Ian. 13, 1948 2,562,592 Woodside et al. July 31, 19 51 FOREIGN PATENTS 1,581 Great Britain Dec. 11, 189 

